Scientists have discovered that a gene linked to Alzheimer’s disease may play a beneficial role in cell survival by enabling neurons to clear away toxic proteins. A study funded by the National Institute on Aging (NIA), part of the National Institutes of Health, shows the presenilin 1 (PS1) gene is essential to the function of lysosomes, the cell component that digests and recycles unwanted proteins. However, mutations in the PS1 gene — a known risk factor for a rare, early onset form of Alzheimer’s disease – disrupt this crucial process.

Ralph Nixon, M.D., Ph.D., of the Nathan Kline Institute, Orangeburg, N.Y., and New York University Langone Medical Center, directed the study involving researchers from the United States, Europe, Japan and Canada. Also supported in part by the Alzheimer’s Association, the study appears in the June 10, 2010, online issue of Cell.

Researchers have theorized for more than a decade that PS1 mutations linked to early-onset Alzheimer’s, a rare form of the disease that usually affects people between ages 30 and 60, may trigger abnormally high levels of beta-amyloid protein to clump together in the brain.

Amyloid deposits and tau protein tangles are hallmarks of both early-onset and the sporadic, more common form of the disease found in people aged 60 and older. These new findings, however, suggest PS1 mutations may play a more general role in the development of early-onset Alzheimer’s.